Like an odometer changing over to all zeros, the numbering scheme on sequential CA license plates will be turning over soon.

Currently, license plates are numbered with the pattern 1ABC123, but those numbers are quickly running out. I personally saw a license plate starting with 9Y on the road recently.

When the numbers do run out, the CA DMV historically reverses the numbering scheme. For example, when they ran out of the ABC123 sequence in the 60s, they issued plates numbered 123ABC, and after that, added a digit and reversed it again for the current 1ABC123 series.